Firearm recoil mechanism with an inertia member releasably held by a magnet



Feb. 3, 1970 VIRQNDA 3,492,749 FIREARM REQOIL MECHANISM WITH AN INERTIA MEMBER RELEASABLY HELD BY A MAGNET Filed Feb. 16, 1968 ll/ I'll ll F764 z/hw@w United States Patent FIREARM RECOIL MECHANISM WITH AN DlERTIA MEMBER RELEASABLY HELD BY A MAGNET Italo D. Vironda, 194 N. Wabash, Battle Creek, Mich. 49017 Filed Feb. 16, 1968, Ser. No. 706,021 Int. Cl. F41c 21/18 11.8. CI. 42-74 12 Claims ABSTRACT OF THE DISCLOSURE A recoil mechanism for a firearm having a sleeve fixedly positioned within the stock of the firearm and an inertia member slideably positioned within the sleeve, and maintained within one end thereof by a releasable holding means, such as a magnet. The inertia member tends to remain stationary when the firearm is moved in response to the recoil forces imposed on the firearm during firing. The recoil forces, which cause the sleeve to move relative to the inertia member, are suflicient to overcome a releasable holding force between the inertia member and the magnet so as to temporarily interrupt the engagement therebetween. The small relative movement between the sleeve and the inertia member thus results in the absorption of a substantially large recoil force. Spring means bias the inertia member back into engagement with the magnet to re-establish the releasable engagement therebetween.

Field of the invention This invention relates in general to firearms and, more particularly, to a mechanism for reducing recoil upon firing.

Background of the invention In the firing of firearms, particularly rifles and shotguns, the development of recoil has long been accepted as an unpleasant but unavoidable condition. Numerous efforts have been undertaken heretofore to bring about reductions if not elimination of such recoil. However, none of these efforts have sufliciently solved the problem so that sports enthusiasts, soldiers, and the like, must expect the shock of recoil upon firing a rifle, shotgun, or the like. Such recoil results often in physical discomfort to the user, which may, in addition to entailing painful bruises, bring about a numbing of the shoulder area.

Furthermore, recoil also is productive of substantial inaccuracy in firing since the force thereof my contribute to the firearm being inadvertantly raised or caused to jump in addition to the fact that the individual user may expectedly be diverted from full control of the firearm in anticipation of the impact of recoil.

While various recoil devices have been developed and utilized on firearms, such as rifles and shotguns, none of these devices, to my knowledge, have been successful in eliminating a substantial portion of the recoil forces transferred to the shoulder of the user during firing of the firearm. Most of the prior recoil devices have utilized a hollow housing member fixedly connected to the firearm with the housing having a plunger or inertia member slideably mounted therein, resilient means, such as coil springs, being provided between the plunger and the housing to absorb the recoil energy as relative movement occurs therebetween during firing. In these devices, however, the amount of recoil force absorbed is substantially directly proportional to the relative movement between the housing and the plunger, which movement results in a compression of the coil spring. Since the coil springs generally have a linear spring rate, and further since the springs utilized in these devices are relatively small, a

small relative movement between the firearm and the plunger is effective in developing only a relatively small force on the spring and thus only a very small portion of the recoil force is effectively absorbed by these devices. While these devices would be capable of absorbing a greater portion of the recoil force if allowed to undergo a substantial amount of relative movement, this is not physically possible since the butt of the rifle is generally held tightly against the shoulder of the user and thus most of the recoil forces are transferred into the shoulder rather than being absorbed by the recoil device.

Accordingly, it is an object of the present invention to provide:

(1) A recoil mechanism adapted for disposition in a firearm, such as a rifle or a shotgun, for substantially eliminating recoil with its attendant undesirable effects.

(2) A recoil mechanism as aforesaid, having an inertia member movably mounted on the firearm and capable of absorbing a substantially large portion of the recoil force or energy by only a small relative movement between the firearm and the inertia member.

(3) A recoil mechanism, as aforesaid, having releasable holding means for holding the inertia member stationary relative to the firearm and for imposing a predetermined holding force thereon, the holding force being overcome during recoil whereby a substantial portion of the recoil force is absorbed due to a small movement of the inertia member relative to the firearm.

(4) A recoil mechanism, as aforesaid, wherein the releasable holding means comprises a magnet for holding the inertia member stationary relative to the firearm with the magnetic force being overcome during recoil whereby a substantial portion of the recoil force is absorbed.

(5 A recoil mechanism, as aforesaid, adapted for easy reception within the stock of a rifle, shotgun, or similar firearm without necessitating costly modification thereof or reduction of effective operation of same.

(6) A recoil mechanism, as aforesaid, which may constitute an accessory for mounting within existing firearms, or may be incorporated into same as a part of the original equipment thereof.

(7) A recoil mechanism, as aforesaid, which is totally enclosed to prevent entry thereinto of moisture and other contaminating materials.

(8) A recoil mechanism, as aforesaid, which is economically produced, is extremely durable and reliable in usage, is installable into existing firearms by the owner thereof without resort to the services of trained individuals, such as gunsmiths, and is of great simplicity in construction and operation.

Other objects and purposes of the invention will be apparent to persons acquainted with apparatus of this general type upon reading the following specification and inspecting the accompanying drawings.

FIGURE 1 is a longitudinal crosssectional view of the preferred form of the recoil mechanism constituting the present invention.

FIGURE 2 is a cross-sectional view taken along the line 11-11 of FIGURE 1.

FIGURE 3 is a cross-sectional view taken along the line IIIIII of FIGURE 1.

FIGURE 4 is a fragmentary longitudinal view in partial vertical section showing the breech and stock portions of a rifle or shotgun incorporating therein a recoil mechanism constructed in accordance with and embodying the present invention.

FIGURE 5 is a longitudinal cross-sectional view of a modified recoil mechanism constructed according to the present invention.

FIGURE 6 is a longitudinal cross-sectional view of still a further modification of a recoil mechanism constructed according to the present invention.

Certain terminology will be used in the following description for convenience and reference only and will not be limiting. The words upwardly, downwardly, rightwardly and leftwardly will designate directions in the drawings to which reference is made. The word forwardly will refer to the normal direction of travel of the firearm projectile and the word rearwardly will refer to the opposite direction, that is, the normal direction of travel of the firearm as caused by the recoil forces. The words inwardly and outwardly will refer to directions toward and away from, respectively, the geometric center of the device and designated parts thereof. Such terminology will include the words above specifically mentioned, derivatives thereof and words of similar import.

Summary of the invention In general, the objects and purposes of the invention are met by providing a recoil device which is positioned within an opening or compartment preferably formed in the stock of a firearm. The recoil device includes a hollow sleeve which is fixedly positioned relative to the firearm stock with an inertia member being slideably mounted within the sleeve. The opposite ends of the sleeve are closed by end walls fixedly secured thereto, the end wall positioned adjacent the back of the firearm having releasable holding means, preferably a magnet, fixedly secured thereto whereby the inertia member, being of a magnetic material, is attracted to the magnet and is normally held in engagement therewith. A spring is provided between the other end of the inertia member and the other end of the sleeve for resiliently urging the inertia member toward and against the magnet. When the firearm is fired, the recoil forces cause the stock of the firearm and the sleeve of the recoil mechanism to be moved rearwardly, during which movement the inertia member tends to remain stationary since it is freely slideably positioned within the sleeve. Since the recoil is generally substantially larger than the magnetic force of attraction developed in the recoil device, the rearward movement of the sleeve by the recoil forces will be sufficient to overcome the magnetic force of attraction between the magnet and the inertia member whereupon the inertia member will become separated and displaced from the magnet. The portion of the recoil force required to overcome the magnetic attraction is thus absorbed within the recoil device and is not transferred to the shoulder of the user. Additional recoil force is absorbed due to compression of the spring by the inertia member as the sleeve continues to move rearwardly. However, a substantially large portion of the recoil forces are almost instantaneously and initially absorbed since only a small relative movement between the inertia member and the stock is necessary to separate the magnet and the inertia member and thus only a small relative movement between the inertia member and the magnet must overcome the full magnetic force. The recoil mechanism is further provided with suitable air passageways to facilitate operation thereof.

Detailed description FIGURES l3 illustrate a preferred embodiment of the present invention, wherein there is illustrated a recoil mechanism indicated generally by the reference numeral 10. The recoil mechanism includes an outer housing member preferably constructed of light metal in the form of a cylindrical sleeve 11 having a substantially cylindrical opening 12 extending throughout the length thereof. The forward end of the sleeve 11 is closed by means of an end wall 13 integrally connected thereto. The rearward end of the sleeve 11 is similarly closed by means of a cap 14 which is fixedly connected to the sleeve by any suitable fastening means, such as a lock pin 16 extending transversely through the cap 14 and the sleeve 11. The inner end of the cap is provided with a counterbore or recess 17 in which a magnet 18 is fixedly or snugly received, the magnet having a surface 19 facing inwardly into the opening contained within the sleeve 11. The sleeve 11 is preferably constructed of a nonmagnetic material, such as aluminum or brass, while the cap 14 may be constructed either of a ferrous or nonferrous material.

Slideably positioned within the opening 12 between the end wall 13 and the magnet 18 is an inertia member 21, which member is constructed generally in the form of a cylindrical plunger member and is of a magnetic material so as to be magnetically attracted by the magnet 18. The inertia member 21 comprises a main body portion 22, preferably of cylindrical configuration, having transverse end face 23 confronting and being adapted to contact the surface 12 of the magnet 18 when the inertia member 21 is held in contact with the magnet 18. The main body portion 22 has a small annular recess 24 formed in the periphery thereof adjacent the end face 23, a compression ring 26, preferably of a durable resilient material such as Teflon, being positioned within the recess 24 so as to slideably engage the inner periphery of the sleeve 11. The compression ring 26 is split as illustrated in FIGURE 3, thereby forming a slOt 25 between the ends thereof for a purpose to be explained hereinafter.

The other end of the main body portion 22 is preferably provided with a boss portion 27 integrally interconnected thereto and extending axially therefrom as illustrated in FIGURE 1. The boss portion 27 is of a smaller diameter than the main body portion 22 and functions as a seat and guide for one end of the compression spring 28 positioned within the opening 12. The other end of the spring 28, which spring may be of a very low stiffness, bears against a rigid, preferably metallic disk 29 which is slideably positioned within the opening 12, which disk 29 in turn bears against a resilient or flexible disk 31 positioned adjacent to and in contact with the end wall 13. The disk 31 is preferably made of leather or other suitable flexible or resilient materials so as to permit partial absorption of the rebound energy of the inertia member.

The boss portion 27 of the inertia member 21 is preferably provided with an undercut groove 32 therein at the junction between the boss portion 27 and the main body portion 22, which undercut groove permits the end coil of the spring 28 to be positioned therein so as to retain the spring in engagement with the inertia member 21. The leading edge 33 of the boss portion 27 is preferably bevelled as illustrated in FIGURE 1 so as to facilitate relative movement between the spring 28 and the inertia member 21.

The inertia member 21 is further provided with an elongated axial passage 34 extending partially therethrough, the passage 34 extending through the boss portion 27 and partially through the main body portion 22, terminating short of the end face 23. A transverse passageway 36 is positioned adjacent the innermost end of the axial passage 34 with the opposite ends of the transverse passage 36 opening into an annular substantially V-shaped groove 37 extending around the periphery of the main body portion 22. The passages 34 and 36 permit air to flow from the one end of the opening 12 (rightward end in FIGURE 1) to the groove 37. Further, the main body portion 22 of the inertia member 21 is preferably slightly smaller than the internal periphery of the sleeve 11 whereby a small clearance exists therebetween whereby air can then pass from the groove 37 axially between the inertia member and the sleeve 11, the air then passing through the slot 25 formed in the compression ring 26 whereupon the air is thus able to enter into the space between the faces 19 and 23 when the inertia member 21 is positioned out of engagement with the magnet 18.

The magnet 18, in cooperation with the magnetic material of the inertia member 21, functions as a releasable holding means capable of developing a predetermined holding force for maintaining the inertia member in engagement within the rearward end of the housing, which holding force decreases in a nonlinear manner as the inertia member moves relative to the housing, thereby absorbing a substantial portion of the recoil force.

Operation The operation of the device embodying the invention will be described in detail hereinbelow for a better understanding of the invention.

In usage, the recoil mechanism illustrated in FIG- URE l, is mounted on or positioned within a firearm 41, such as is schematically illustrated in FIGURE 4. The normally wooden stock 42 of the firearm 41 is provided with an opening 43 therein, which opening is substantially axially parallel to the barrel 44 of the firearm 41. The opening 43 generally has a cylindrical configuration whereby the sleeve 11 will be receivable therein. The opening 43 is preferably formed as a blind bore so as to form a front face 46, with the forward end wall 13 of the sleeve 11 being positioned adjacent thereto. A resilient bufier 61 is preferably positioned between the end wall 13 and the front face 46 to prevent the imposition of large impact loads on the wooden stock. The rearward end of the opening 43 is closed by means of a butt plate 47 secured to the stock 42 by means of screws 48. When the recoil mechanism 10 is positioned in the opening 43 and the butt plate 47 is fixedly secured to the stock 42, the end plate 14 of the recoil mechanism preferably bears against the butt plate 47 so as to prevent any axial movement of the sleeve 11 relative to the firearm 41. However, since the axial length of the opening 43 may substantially exceed the length of the sleeve 11, a plurality of resilient spacers 62 may be positioned between the end plate 14 and the butt plate 47 to prevent any axial movement of the sleeve within the opening. Further, if the sleeve 11 is of substantially smaller diameter than the opening 43, any suitable means can be used so as to cause the sleeve 11 to be snugly held within the opening 43, such as by wrapping the sleeve 11 with tape.

With the recoil mechanism 10 thus installed within the stock 42 of the firearm 41, the user is free to fire the firearm 41 with a sense of assurance that the theretofore experienced powerful recoil will be substantially minimized or eliminated.

Before the firearm is fired, the recoil mechanism will be positioned substantially as illustrated in FIGURE 1, that is, the inertia member 21 will be positioned by the spring 28 adjacent the rearward end of the firearm and held in abutting engagement with the exposed face 19 of the magnet 18 by the magnetic force of attraction existing between the two abutting members. When the rifle or shotgun is fired, the recoil forces will be imposed on, and transferred rearwardly through, the stock 42 so as to tend to move the firearm rearwardly against the shoulder of the user. The sleeve 11 of the recoil mechanism 10, being fixedly held relative to the stock 42, will likewise be moved rearwardly due to the recoil forces. However, since the inertia member 21 is freely slideably positioned within the sleeve 11, it will tend to remain stationary and thus the recoil forces imposed on the sleeve 11 and the associated rearward movement caused thereby will tend to cause the sleeve 11 to move rearwardly in an axial direction relative to the inertia member 21 so as to causerelative axial movement to occur therebetween.

In order for the sleeve 11 and the magnet 18 fixedly secured thereto to move axially rearwardly relative to the inertia member 21, it is first necessary for the recoil forces to overcome the holding force or magnetic force of attraction which exists between the magnet 18 and the inertia member 21. Since the recoil forces are generally substantially larger than the magnetic force of attraction, the recoil force will be sufiicient to accomplish this and thereby cause the sleeve 11 and the magnet 18 to move axially rearwardly relative to and away from the inertia member 21. However, in overcoming this magnetic force of attraction, a portion of the recoil force is thus absorbed by the recoil mechanism 10 and is thus not transferred to the shoulder of the user of the firearm. Further, this portion of the recoil force is absorbed almost instantaneously upon firing since the magnetic holding force decreases in a nonlinear exponential manner, that is, the magnetic force of attraction decreases inversely in proportion to the square of the distance separating the magnetic members. Thus, only a small relative axial movement is needed to overcome a substantial portion of the magnetic holding force.

After the magnetic force of attraction has been overcome, still further absorption of the recoil forces is obtained since additional relative axial movement between the inertia member 21 and the sleeve 11 causes the compression spring 28 to be compressed between the end wall 13 and the hub portion 27, which force of compression is substantially directly proportional to the amount of compression of the spring whereby the recoil force absorbed by the recoil mechanism is thus substantially linear after the magnetic force of attraction is initially overcome.

During the above-described recoil movement, whereupon the inertia member 21 is relatively moved away from the member 18, air enclosed within the opening 12 in surrounding relationship to the coil spring 28 passes through the axial passage 34 and the transverse passage 36 into the groove 37, whereupon the air then passes through the clearance between the inertia member 21 and the sleeve 11 and through the slot 25 formed in the compression ring 26 into the cylindrical space between the end faces 19 and 23. In this manner, the pressure forces exerted on the inertia member 21 by the air enclosed within the sleeve 11 are substantially balanced on each end of the system. Therefore, no substantial compression of the air is effected so as to impede operation of the device. Further, the slit formed in the compression ring 28 provides an additional function in that it restricts the flow of air back through the passages 34 and 36 into the opening 16 adjacent the rightward end of the device as the inertia member 21 is returned into its normal position by means of the compression spring 28, thereby minimizing rebound of the inertia member.

Modification FIGURES 5 and 6 illustrate therein modified recoil mechanisms 10A and 10B, respectively, which are substantially similar to the preferred embodiment of the recoil mechanism 10 illustrated in FIGURE 1. Parts of the recoil mechanism 10A illustrated in FIGURE 5 will be referred to by the same reference numerals designating corresponding parts of the recoil mechanism 10 illustrated in FIGURE 1 with the suflix A added thereto. Similarly, parts of the recoil mechanism 10B of FIGURE 6 will be referred to by the same reference numerals designating corresponding parts of the preferred embodiment of the recoil mechanism 10 illustrated in FIGURE 1 with the suflix B added thereto.

As illustrated in FIGURE 5, the recoil mechanism 10A comprises a substantially cylindrical shell 11A having a substantially solid inertia member 21A slideably mounted therein, a compression spring 28A being positioned between the inertia member and the disk 29A, which in turn bears against a leather disk 31A positioned adjacent the end wall 13A of the sleeve. The metal disk 29A, the leather washer 31A and the end 'wall 13A are provided with an opening 51 extending therethrough, which opening functions as a vent for permitting air to pass therethrough when the inertia member is moved in a reciprocating manner within the sleeve 11A. A screen or filter 58 is preferably positioned between the disk 29A and the washer 31A to prevent entry of contaminating materials into the interior of the sleeve 11A. The other end of the sleeve has a cap member 14A fixedly positioned therein. However, in this embodiment, the magnet 18A is snugly and tightly positioned within a recess 17A formed in the end of the inertia member 21A and reciprocates therewith. The cap 14A is thus made of a ferrous material so as to be magnetically attracted to the magnet 18A.

7 The embodiment illustrated in FIGURE operates in substantially the same manner as the embodiment illustrated in FIGURE 1 described above and accordingly further description of the operation thereof is not believed necessary.

A still further embodiment is illustrated by the recoil mechanism 10B shown in FIGURE 6. This embodiment also includes a substantially cylindrical shell 11B having an integral end wall 13B closing one end thereof and a ferrous or magnetic cap member 14B fixedly interconnected to the Sleeve and closing the other end thereof. The inertia member 21B is slideably mounted within the opening 12B formed within the sleeve and comprises a substantially hollow shell 56 having a heavy core 57 therein, the shell 56 preferably being of a ferrous material while the core 57 may be of lead or similar material. The magnet 18B is fixedly interconnected to the shell 56 of the inertia member 21B by any suitable means, such as by welding, whereupon the magnet is then movable with the inertia member. The magnet 18B magnetically attracts the ferrous cap member 14B whereupon the inertia member is then normally maintained in the position illustrated in FIG- URE 6. A conventional compression spring 28B is positioned between the other end of the inertia member 21B and a leather or fiber disk 31B positioned adjacent the end Wall 13B. The end wall 13B and the fiber disk 31B are provided with a first vent opening 52 extending therethrough and the end cap 14B is provided with a similar vent opening 53 extending therethrough. The vent openings 52 and 53 permit air to pass therethrough when the inertia member 21B reciprocates within the sleeve 12B.

The embodiment illustrated in FIGURE 6 also operates in substantially the same manner as the preferred embodiment of FIGURE 1, explained above, and accordingly further description of the operation is not believed necessary.

In view of the foregoing, it will be seen that a recoil mechanism constructed in accordance with the present invention may be readily installed in any existing type of firearm without requiring the skilled services of a gunsmith, but may be readily installed by the average firearm user without costly modification of the particular firearm. Furthermore, as is evident from the foregoing, the recoil mechanism hereinabove described will permit comfortable, consistently accurate and reliable usage of substantially powerful firearms obviating the various attendant unpleasant effects of the recoil which currently had been considered as unavoidable conditions of firearm usage.

It will also be obvious that, in the recoil mechanism described above, the magnet 18 used for holding inertia member 21 stationary relative to the sleeve 11 can be positioned either on the sleeve or on the inertia member, as desired. Still further, a pair of magnets could be utilized with one of the magnets being mounted on the sleeve and the other of the magnets being mounted on the inertia member if so desired. While all of the recoil mechanisms illustrated and discussed above have been of a cylindrical configuration, it will be recognized that this configuration is utilized merely for convenience in manufacture and installation and any other desired cross-sectional configuration can obviously be utilized.

The recoil mechanism illustrated in FIGURES 1-3 is preferred since this recoil mechanism is substantially and completely enclosed, the outer sleeve 11 not having any vents or openings passing therethrough. This is advantageous since such a closed construction thus prevents moisture or other contaminating materials from entering into the interior of the recoil mechanism, whereupon the recoil mechanism will thus not be susceptible to rust or fouling. Such a recoil mechanism thus possesses durability and dependability of operation and will require very little maintenance and/ or repair.

The inertia member 21 used in the recoil mechanism of FIGURE 1 is preferably constructed of a magnetic or ferrous material. However, it will be obvious that only the axial end portion of the inertia member 21 adjacent the end face 23 need be of a magnetic material so as to be magnetically attracted by the magnet 18. The remainder of the plunger 21 could, if desired, be of a nonmagnetic material.

While the releasable holding means used in the recoil mechanism of the present invention has been disclosed as preferably comprising a magnet, other suitable holding devices could be utilized. Such holding means must be able to develop a predetermined or threshold holding force between the inertia member and the housing with the holding force being overcome by a small relative movement therebetween. For example, the end cap 14 and the adjacent end of the inertia member 21 could be formed With a mechanical snap-like connection therebetween. Alternatively, sleeve 11 could have a spring-biased detent mounted thereon and engageable with the inertia member 21 for holding same, the detent disengaging the inertia member and permitting same to move relative to the sleeve when subjected to an axial force of predetermined magnitude. Accordingly, the present invention encompasses not only the holding means disclosed above, but also other holding devices which function in a substantially similar manner.

The embodiments of the invention in which I claim an exclusive property or privilege are defined as follows:

1. A recoil mechanism adapted to be mounted on a firearm for absorbing at least a portion of the recoil energy, said mechanism comprising:

housing means adapted to be fixedly mounted on said firearm, and housing means having an opening therethrough and wall means at least partially closing opposite ends of said opening; inertia member means mounted within said opening for movement relative to said housing means; and

releasable holding means creating a holding force of a predetermined magnitude for releasably holding said inertia member means in a normal position substantially adjacent said wall means at one end of said opening with said holding force decreasing below said predetermined magnitude as said inertia member moves away from said normal position, the recoil energy upon firing tending to overcome the holding force so as to move said inertia member means in a direction toward the other end of said opening.

2. A recoil mechanism as defined in claim 1, further including:

resilient means within said opening and positioned between said inertia memlber means and said wall means adjacent the other end of said opening for normally urging said inertia member means in a direction toward said normal position.

3. A recoil mechanism adapted to be mounted on a firearm for absorbing at least a portion of the recoil energy, said mechanism comprising:

housing means adapted to be fixedly mounted on said firearm, said housing means having an opening therethrough and Wall means at least partially closing opposite ends of said opening; inertia member means mounted within said opening for movement relative to said housing means; and

releasable holding means creating a holding force for releasably holding said inertia member means in a normal position substantially adjacent said wall means at one end of said opening, said holding means including magnet means creating a magnetic holding force for maintaining said inertia member in said normal position, the recoil energy upon firing tending to overcome the holding force so as to move said inertia member means in a direction toward the other end of said opening.

4. A recoil mechanism as defined in claim 3, wherein:

said wall means including a cap member fixedly secured to said housing adjacent said one end of said opening;

said magnet means including a magnet fixedly secured to said cap member and at least a portion of said inertia member means being of a magnetic material so as to be magnetically attracted to said magnet whereby said inertia member means is normally maintained in a position substantially adjacent to said magnet.

5. A recoil mechanism as defined in claim 3, wherein:

said wall means includes a cap member interconnected to said housing means adjacent saidone end of said opening, at least a portion of said cap member'being of a magnetic material;

said magnet means including a magnetfixedly secured to said inertia member means substantially adjacent the end thereof confrontingsaid cap member, said cap member being magnetically attracted to said magnet whereby said inertia membef means is normally maintained in a position substantially adjacent said cap member.

6. A recoil mechanism as defined in claim 3, further including:

resilient means within said opening and positioned between said inertia member means and said wall means adjacent the other end of said opening for normally urging said inertia member means in a direction toward said normal position. i

7. A recoil mechanism as defined in claim 3, wherein:

said housing means comprises alsubstantilally cylindrical sleeve with said opening extending substantially longitudinally throughout the length of said sleeve;

said wall means including a first endwall member fixedly secured to said sleeveadjacnt said one end of said opening and a. second end wall member fixedly secured to said sleeve adjacent the other end of said opening;

said inertia member means including a substantially cylindrical plunger slideably positioned within said opening for slideable movement relative to said sleeve, said plunger being normally positionedwithin said opening adjacent said one end thereof whereby one end of said plunger is positioned closely adjacent to said first end wall member; and

spring means positioned within said opening between said second end wall member and the other end of said plunger for resiliently urging said plunger toward said normal position.

8. A recoil mechanism as defined in claim 7, wherein:

said magnet means includes a magnet fixedly secured to said first end wall substantially adjacent said one end of said opening;

at least a portion of said plunger being of a magnetic material whereby said plunger is thus magnetically attracted toward said magnet.

9. A recoil mechanism as defined in claim 8, wherein said opening as defined by said cylindrical sleeve and said first and second end walls is totally enclosed so as to substantially prevent the entrance of air or contaminating materials therein.

10. A recoil mechanism as defined in claim 9, further including:

passageway means interconnecting portions of said opening adjacent opposite ends of said plunger, at least a portion of said passageway means being formed in said plunger and extending axially thereof;

a compression ring being mounted on said plunger adjacent the one end thereof in surrounding relationship thereto with said compression ring being in slideable engagement with said sleeve, said compression ring being split so as to define a small slot between the adjacent ends thereof, said slot comprising another portion of said passageway means.

11. A recoil mechanism as defined in claim 7, wherein:

said first end wall is of a magnetic material;

said magnet means including a magnet fixedly secured to said plunger adjacent the one end thereof;

12. A recoil mechanism as defined in claim 7, wherein:

at least one of said end walls has a vent opening extending therethrough.

References Cited UNITED STATES PATENTS 3,176,424 4/ 1965 Hoge 42-74 3,300,889 1/ 1967 Baker 42--74 3,365,829 1/ 1968 Shockey 42-1 3,381,405 5/1968 Edwards 42-74 3,405,470 10/1968 Wesemann 42-74 BENJAMIN A. BORCHELT, Primary Examiner C. T. JORDAN, Assistant Examiner 

